Funny thing is they turn up in strange places. The gears are marked and easy to identify. I think I have a couple of sets now both NOS and used. I won't mention any names but I recently was delivered a remote tranny from a respected builder/ supplier and right there was a O/D first motion shaft input gear all torqued and ready. I don't think there are any small shaft A+ idlers. 

Alex, I was working of getting these very heavy Canadian bumpers to the meet this year for you. Then I heard you could not make it. I hope you insured your trip. Steve (CTR)

They are.

Later A+ gearsets can be overdriven on the Primary gear and the 1st motion input gear.  I have a couple of sets kicking about, that I really ought to dig out and photograph one day... I know Steve has expressed an interest when i do.

I'm not really good with math. I did work out a chart with 145/10, 165/10, 145/12 and 165/12/60 series. I included CWPs 4.35, 4.10, 3.9, 3.76, 2.76, 3.44, 3.1, 2.95 and the different size tires for what I figure to be around 2.55/2.56. I have checked 2.55 with 145/12 at 3000 and 4000 with tach and GPS. I have done several extra wide ratio trannys with the 2.76 double O/D drops and couple of std wide ratio late gear sets with 2.76 and a single O/D drop. While I rebuilt that engine with a SW5-07 I have not driven the car but the owner seems very happy with the highway performance. 

Sorry if we got off track. There are so many options and looking at them on paper gives me an idea of what each will do. Steve (CTR)

Steve, the old mini speed/rpm charts were based on 10" wheels with 19.3" tire outside diameter.  That would mean your drop gears are 1:0.9 ratio.

It would seem to me you are almost at the race engine spec. Higher compression ratio would get you there. With that much cam I'd think you could have gone to 11 to 1 without issues. I have come to think of the 3.44 as the new 4.11. If you look at the math there is only 1.8 mph difference per 1000 rpm between the 3.1 and 3.44. If you go to a 3.9 you are looking at a 3.75 difference per 1000 rpm. It is hard to have it both ways. I run the extra wide ratio gear set, 2.76 CWP and two O/D drop gears. Running 145 tires I get bad wheel spin in the lower gears and roll 70 at 3000 rpm. Since all my driving is at 2000/3000 rpm I don't need a lot of cam. Steve (CTR)

Wow, that 1867 Morris must be the oldest around.....

I currently have a 3.1 final drive in my 1968 Cooper S with 1275, 266 cam.  I have just driven the car on the road around town with new motor so I cannot tell if I like it or not, only 3 miles total.  I did have a 1275 S in the early 90's with a VP3 cam which is what the 286 is I guess and I loved that cam and motor with a 3.44.  Damn loud on the highway though.

Dogscarf
1867 Morris Cooper S MKI
1968 Morris Cooper S MKII

With that cam you want a 3.44. It doesn't come awake until after 3500rpm and you'll love it when you get it up around 5-6K.

Sporty, twisty, hilly driving would call for the 3.44

I have cars with both.....  the 3.1 is fine around town with an 1130...about a stock 1275 performance.  Highway cruising is much nicer with the 3.1, but how much are you doing really?
The 3.44 much better in traffic with a 998. 

I prefer the hwy in the 1130 with 3.1 rather than my 1275 with 3.44

First gear in a straight cut 'box makes anything higher than a 3.44 utterly miserable to live with in traffic.
I have a 3.1 and an ST gearset in Tubbs, and the ability to do 45mph in first is countered by much clutch abuse off the line, and heavily laden hill starts can be very tricky. 

Fellow Minioids,  I am in the process of rebuilding the engine and gearbox for my 1967 Morris Cooper S (Aussie).  The engine has a light flywheel, backplate, 286 cam, ported head, LCB, .040 10.25 to 1, 1.5 ratio rockers (optional) and more.  The gearbox has a straight-cut gearset, 4 syncro.  I have both 3.1 and 3.44 gears to choose from.  I want to do sported backroad driving and some highway.  So, which gearset would be better?  Would the engine bog down with a taller first gear and a 286 cam?

Dogscarf